Police say they were called to the main Senate House building on campus after university officials reported an assault on a security guard by a solitary member of protest group Warwick For Free Education.

Three men were later arrested – one on suspicion of assault and two on suspicion of obstructing police. The trio have not been charged but were released on bail until January.

They have been told they are not allowed to visit the university campus under bail conditions.

Hattie Craig, national campaign manager for NCAFC, said: “I think it is disgusting the way students have been treated for protesting for free education.

“They were sat in a foyer and they were charged by police. We can see from the video it was extremely violent treatment. It is a worrying indication of the crackdown on student protests.

“We have never seen a case where CS gas has been used on student protesters before these images.”

The footage of the incident has sparked outrage in some quarters and campaign group NCAFC has helped organise protests in response across the country today – including one at Warwick University today from 3.30pm.

Further demonstrations are planned in Leeds, London and Manchester and Miss Craig added that the reaction to the video footage of last night’s protest was the catalyst for protests springing up across the country today.

She said: “Most of these are spontaneous responses to what many saw as terrible, brutal attacks on students.

“It is a testament to the student movement that so many saw what happened and want to coordinate their own demonstrations in response.”

She added: “We are going to continue our campaign for free education.

“The crackdown is illustrative of university management and police fears that this is moving on and could be successful and they are determined to crush it from the beginning.”

A Warwick University spokesman said no extra security measures would be taken during today’s planned protest on campus.

West Midlands Police and Crime Commissioner David Jamieson earlier told the Telegraph he had no reason to believe officers had acted disproportionately – but pledged any complaints would be properly investigated.